Evans Water Engineers


+44 1566 782285 · www.evans-engineering.co.uk · email sales@evans-engineering.co.uk

What next?

(Planning a waterpower system)

This need not be a difficult or daunting process. It is important not to over complicate things, as the paperwork can cause a disproportionate burden on smaller projects. Remember you are dealing with a farm or domestic scheme and not the Aswan Dam! It is a great mistake to rush in and select a turbine before the background information and issues have been addressed. It is usual for the turbine manufacturer to recommend and present the advantages and disadvantages of any particular design.

The whole field of small-scale waterpower development has been semi-dormant for half a century and the requirements for micro-hydro as a ‘green energy saving technology’ are a bit different to designing projects for ‘early stage’ rural electrification.

The great variety of sites and equipment can be confusing, so this planning system should make the whole process much easier. We use a few simple ‘labels’ to describe projects and equipment, (Hillstream, Millstream, Pico, micro, mini, etc). These are added to as the design progresses. We divide our projects into several different groups, each having several layouts, nominal outputs, and turbine types. Other options include material and control systems

Only some of the issues covered here will be applicable to your project but it should help you avoid costly mistakes and delays in getting your project completed. I have also produced a series of more detailed information sheets covering the different turbine systems, typical sites and most common applications.

The subsequent design stage will lead to the site survey, contract and implementation stages. Building and operating your own hydro plant will never be as simple as turning on a switch and paying an electricity bill, but there are many non-technical people who get a great deal of pleasure in producing there own power (from a shed at the bottom of the garden) as well as obtaining a good return on their investment.

Preliminary design

The preliminary data collecting stage is necessary to make an initial assessment of the potential output, possible problems and to produce a budget cost.

A suitable site is the starting point, if you don’t already own it, you will need to purchase it or lease it. If you simply wish to get on with it or continue what you are already doing, it is vital that you don’t any environmental damage or upset neighbours or fishermen.

Outline information, consisting of a map, plan or sketch, together with half a dozen photographs will get the ball rolling. Should you already have river flow data, survey data or a full report, these should help greatly with my initial appraisal. A video or aerial photographs may be appropriate in illustrating the general lie of the land and the extent of your property.

The power required, or more importantly the energy you require to run your home or business, now and in the foreseeable future, can be gleaned from your old electricity and heating bills and this will indicate the proportion of your total energy requirement that can be met by the proposed scheme. The value of each unit (kWh) of electricity or heat delivered by the plant can be calculated. This will usually be the ‘replacement cost’ of what you are using now.

Work out a budget that gives you an acceptable return on your investment. If you are planning to borrow the capital necessary, the return will have to cover both the cost of borrowing and paying back the capital. I suggest that a target figure of 15% should be attractive considering the long term and environmentally friendly nature of the project.

The time-scale for a complete project is seldom less than 12 months, since it can involve several outside agencies. Installation work should if possible be scheduled for the summer months.

The environmental impact of your project should be minimal, both in terms of visual impact and the river ecology. If designed properly it should not be obvious that there is a waterpower installation in place at all. Problems in this area can cause considerable delays, expense and litigation if not handled correctly. A commitment to the ideals of self-sufficiency and environmental stewardship will help you complete a successful project.

Planning permission may be required if your project involves the construction of a powerhouse or other fixed structures. If you are reusing an existing building or mill or the equipment is portable, below ground or less than 3 metres high, the local planning department may not require planning permission. Special cases may include listed buildings, and areas of historic and scientific interest.

The water Resources Acts have caused a lot of difficulty for hydro developers, often this has not been because of restrictions but because of omissions and over-sights in the drafting of the legislation. Waterpower is a minority interest and has not in the past had an appropriate body to look after its interests. The different aspects of legislation cover water abstraction, flood prevention, drainage, impounding, pollution control and fishery protection.

After you have gathered together this primary data and preferably completed a questionnaire, I will come back to you with some outline proposals and budget prices. This will lead to more detailed design work culminating in a site survey to confirm both the site details and contract requirements.